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JP2013084566A - Nonaqueous electrolytic secondary cell - Google Patents

Nonaqueous electrolytic secondary cell Download PDF

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JP2013084566A
JP2013084566A JP2012153335A JP2012153335A JP2013084566A JP 2013084566 A JP2013084566 A JP 2013084566A JP 2012153335 A JP2012153335 A JP 2012153335A JP 2012153335 A JP2012153335 A JP 2012153335A JP 2013084566 A JP2013084566 A JP 2013084566A
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positive electrode
negative electrode
secondary battery
lithium
active material
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Hideo Yanagida
英雄 柳田
Kazuki Takimoto
一樹 瀧本
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Subaru Corp
Nippon Chemical Industrial Co Ltd
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Nippon Chemical Industrial Co Ltd
Fuji Heavy Industries Ltd
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Priority to JP2012153335A priority Critical patent/JP2013084566A/en
Priority to US13/605,707 priority patent/US20130084499A1/en
Priority to CN2012103627345A priority patent/CN103035921A/en
Priority to EP12186164A priority patent/EP2575201A1/en
Publication of JP2013084566A publication Critical patent/JP2013084566A/en
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    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/05Accumulators with non-aqueous electrolyte
    • H01M10/052Li-accumulators
    • H01M10/0525Rocking-chair batteries, i.e. batteries with lithium insertion or intercalation in both electrodes; Lithium-ion batteries
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/36Selection of substances as active materials, active masses, active liquids
    • H01M4/362Composites
    • H01M4/364Composites as mixtures
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/36Selection of substances as active materials, active masses, active liquids
    • H01M4/48Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides
    • H01M4/52Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron
    • H01M4/525Selection of substances as active materials, active masses, active liquids of inorganic oxides or hydroxides of nickel, cobalt or iron of mixed oxides or hydroxides containing iron, cobalt or nickel for inserting or intercalating light metals, e.g. LiNiO2, LiCoO2 or LiCoOxFy
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M4/00Electrodes
    • H01M4/02Electrodes composed of, or comprising, active material
    • H01M4/36Selection of substances as active materials, active masses, active liquids
    • H01M4/58Selection of substances as active materials, active masses, active liquids of inorganic compounds other than oxides or hydroxides, e.g. sulfides, selenides, tellurides, halogenides or LiCoFy; of polyanionic structures, e.g. phosphates, silicates or borates
    • H01M4/5825Oxygenated metallic salts or polyanionic structures, e.g. borates, phosphates, silicates, olivines
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/42Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M2010/4292Aspects relating to capacity ratio of electrodes/electrolyte or anode/cathode
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2220/00Batteries for particular applications
    • H01M2220/20Batteries in motive systems, e.g. vehicle, ship, plane
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10Energy storage using batteries
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02TCLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00Road transport of goods or passengers
    • Y02T10/60Other road transportation technologies with climate change mitigation effect
    • Y02T10/70Energy storage systems for electromobility, e.g. batteries

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  • Chemical & Material Sciences (AREA)
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Abstract

PROBLEM TO BE SOLVED: To provide a high-output and high-capacity safe nonaqueous electrolytic secondary cell which has a positive electrode including lithium vanadium phosphate, which has good cycle characteristic, and which is arranged so that neither abnormal heat generation of the cell nor combustion thereof is caused even if a short circuit is caused inside the cell owing to a conductive metallic foreign material or the like stuck thereinto.SOLUTION: The nonaqueous electrolytic secondary cell comprises: a positive electrode active material which includes carbon-coated lithium vanadium phosphate and a lithium nickel complex oxide; and a negative electrode active material which includes a carbon-based active material capable of releasing and absorbing lithium ions. If the negative electrode initial charge capacity per unit area is denoted by x [mAh/cm], and the positive electrode initial charge capacity per unit area is denoted by y [mAh/cm], the relation of x and y meets the following condition: 0.6≤y/x≤0.92.

Description

本発明は、非水電解質二次電池に関し、特に、正極活物質としてリン酸バナジウムリチウム及びリチウムニッケル複合酸化物を含む非水電解質二次電池に関する。   The present invention relates to a nonaqueous electrolyte secondary battery, and more particularly to a nonaqueous electrolyte secondary battery containing lithium vanadium phosphate and a lithium nickel composite oxide as a positive electrode active material.

リチウムイオン二次電池等の非水電解質二次電池は、近年、電気機器等の電源として使用されており、さらに、電気自動車(EV、HEV等)の電源としても使用されつつある。そして、リチウムイオン二次電池等の非水電解質二次電池は、その更なる特性向上、例えばエネルギー密度の向上(高容量化)、出力密度の向上(高出力化)やサイクル特性の向上(サイクル寿命の向上)、高い安全性等が望まれている。   In recent years, non-aqueous electrolyte secondary batteries such as lithium ion secondary batteries have been used as power sources for electric devices and the like, and are also being used as power sources for electric vehicles (EV, HEV, etc.). Non-aqueous electrolyte secondary batteries such as lithium ion secondary batteries further improve their characteristics, such as energy density (higher capacity), output density (higher output), and cycle characteristics (cycle). Improvement of life), high safety, etc. are desired.

現在、小型電気機器等に使用されているリチウムイオン二次電池の多くはLiCoO2等のリチウム複合酸化物を正極活物質として用いたものであり、高容量、高寿命の蓄電デバイスを実現している。しかしながら、これらの正極活物質は、異常発生時の高温高電位状態等において、激しく電解液と反応し、酸素放出を伴って発熱し、最悪の場合、発火に至る場合がある等の問題がある。 Currently, many of the lithium ion secondary batteries used in small electric devices and the like use lithium composite oxides such as LiCoO 2 as a positive electrode active material, realizing high-capacity and long-life storage devices. Yes. However, these positive electrode active materials have problems such as high temperature and high potential at the time of occurrence of abnormality, which reacts violently with the electrolyte and generates heat accompanied by oxygen release, which may lead to ignition in the worst case. .

近年、高温高電位状態でも熱安定性に優れた正極活物質としてオリビン型Fe(LiFePO4)や類似結晶構造を有するオリビン型Mn(LiMnPO4)等が検討され、一部、電動工具用途等に実用化に至っている。しかしながら、LiFePO4は、作動電圧がLi/Li+基準に対して3.3〜3.4Vであり、汎用電池に使用されている正極活物質の作動電圧に比べて低いため、エネルギー密度や出力密度の点で不十分である。また、LiMnPO4は、作動電圧がLi/Li+基準に対して4.1Vであり、160mAh/gの理論容量を有することから高エネルギー密度の電池が期待できるが、材料自身の抵抗が高く、高温でMnが溶解する等の問題もある。 In recent years, olivine-type Fe (LiFePO 4 ) and olivine-type Mn (LiMnPO 4 ) having a similar crystal structure have been studied as positive electrode active materials excellent in thermal stability even at high temperatures and high potentials. It has been put to practical use. However, since LiFePO 4 has an operating voltage of 3.3 to 3.4 V with respect to the Li / Li + standard and is lower than the operating voltage of the positive electrode active material used for general-purpose batteries, the energy density and output It is insufficient in terms of density. In addition, LiMnPO 4 has an operating voltage of 4.1 V with respect to the Li / Li + standard and has a theoretical capacity of 160 mAh / g. Therefore, a high energy density battery can be expected, but the resistance of the material itself is high. There are also problems such as dissolution of Mn at high temperatures.

したがって、オリビン型を用いたとしても、高容量、高出力、高寿命、高い安全性を併せ持つ電池は実現できていない。   Therefore, even if the olivine type is used, a battery having high capacity, high output, long life, and high safety cannot be realized.

一方、最近、熱安定性に優れた類似正極活物質として、ナシコン型のリン酸バナジウムリチウム、すなわちLi32(PO43が注目されている(例えば、特許文献1)。Li32(PO43は、作動電圧がLi/Li+基準に対して3.8Vであり、各電位プラトーに応じて、130〜195mAh/gの大きな容量を示す。更に、オリビン鉄材料でも採用された正極活物質表面への導電性カーボン被膜形成技術により、電子伝導性が向上され、高出力化が実現されている。 On the other hand, recently, NASICON-type lithium vanadium phosphate, that is, Li 3 V 2 (PO 4 ) 3 has attracted attention as a similar positive electrode active material excellent in thermal stability (for example, Patent Document 1). Li 3 V 2 (PO 4 ) 3 has an operating voltage of 3.8 V with respect to the Li / Li + standard, and shows a large capacity of 130 to 195 mAh / g depending on each potential plateau. Furthermore, the electroconductivity carbon film forming technique on the surface of the positive electrode active material, which is also adopted in the olivine iron material, improves the electron conductivity and realizes high output.

特表2001−500665号公報Special Table 2001-2001655 gazette

従来、電池の特性安定化、信頼性の確保、安全性の確保、及び高エネルギーを実現するために、負極及び正極の出力特性を考慮して、単位面積当たりの負極初度充電容量をx[mAh/cm2]、単位面積当たりの正極初度充電容量をy[mAh/cm2]としたときのxとyとの関係が、0.95<y/x<1となるように設計されている。しかし、高出力且つ高容量の電池において、例えば、導電性金属異物等の突き刺しによる内部短絡等が発生した場合、瞬間的に大量のリチウムイオンが負極側から正極側に放出される。正極にLi32(PO43とリチウムニッケル複合酸化物を含む非水電解質二次電池においては、内部短絡等が発生した場合、正極側でのリチウムイオンの受け入れ性は良好であるが、負極側でのリチウムイオンの供与性が問題であった。この供与性が低いと、負極の発熱が顕著となりセルの異常加熱や発熱が生じる。最悪の場合には発火に至る。非水電解質二次電池を車載等の移動体に搭載した場合には、交通事故等により導電性金属異物等の突き刺しが起こることが十分に考えられるため、上記のセルの異常発熱や発火は防止しなければならない。 Conventionally, in order to stabilize battery characteristics, ensure reliability, ensure safety, and achieve high energy, the negative electrode initial charge capacity per unit area is set to x [mAh in consideration of output characteristics of the negative electrode and the positive electrode. / Cm 2 ], and the relationship between x and y when the positive electrode initial charge capacity per unit area is y [mAh / cm 2 ] is designed to be 0.95 <y / x <1. . However, in a high-power and high-capacity battery, for example, when an internal short circuit or the like due to piercing of a conductive metal foreign material or the like occurs, a large amount of lithium ions is instantaneously released from the negative electrode side to the positive electrode side. In a nonaqueous electrolyte secondary battery including Li 3 V 2 (PO 4 ) 3 and a lithium nickel composite oxide on the positive electrode, when an internal short circuit occurs, the lithium ion acceptability on the positive electrode side is good. The lithium ion donating property on the negative electrode side was a problem. If this donating property is low, heat generation of the negative electrode becomes remarkable, and abnormal heating or heat generation of the cell occurs. In the worst case, it will ignite. When a non-aqueous electrolyte secondary battery is mounted on a moving body such as an in-vehicle vehicle, it is fully possible that a conductive metal foreign object or the like may be stabbed due to a traffic accident or the like. Must.

従って、本発明の目的は、正極にリン酸バナジウムリチウムを含む高出力且つ高容量の非水電解質二次電池において、導電性金属異物等の突き刺しによる内部短絡等が発生した場合でも、セルの異常発熱や発火を引き起こさない安全で且つサイクル特性の良好な非水電解質二次電池を提供することにある。   Accordingly, the object of the present invention is to provide a high-power and high-capacity non-aqueous electrolyte secondary battery containing lithium vanadium phosphate as a positive electrode, even if an internal short circuit or the like due to piercing of a conductive metal foreign material occurs. It is an object of the present invention to provide a non-aqueous electrolyte secondary battery that is safe and has good cycle characteristics that does not cause heat generation or ignition.

上記目的を達成するため、本発明は、カーボンを被覆したリン酸バナジウムリチウム及びリチウムニッケル複合酸化物を正極の活物質に含み、且つリチウムイオン脱挿入可能なカーボン系活物質を負極の活物質に含み、単位面積当たりの負極初度充電容量をx[mAh/cm2]、単位面積当たりの正極初度充電容量をy[mAh/cm2]としたときのxとyとの関係が、0.6≦y/x≦0.92となることを特徴とする非水電解質二次電池を提供する。なお、リン酸バナジウムリチウムは、Lix2-yy(PO4zで表され、Mが原子番号11以上の金属元素であって、例えば、Fe、Co、Mn、Cu、Zn、Al、Sn、B、Ga、Cr、V、Ti、Mg、Ca、Sr、Zrからなる群より選ばれる一種以上であり、且つ1≦x≦3、0≦y2、2≦z≦3を満足する材料を含む。例示すれば、Li32(PO43である。 In order to achieve the above object, the present invention provides a cathode active material containing carbon-coated lithium vanadium phosphate and a lithium nickel composite oxide, and a lithium ion detachable carbon-based active material as an anode active material. The negative electrode initial charge capacity per unit area is x [mAh / cm 2 ], and the positive electrode initial charge capacity per unit area is y [mAh / cm 2 ]. Provided is a nonaqueous electrolyte secondary battery in which ≦ y / x ≦ 0.92. Note that lithium vanadium phosphate is represented by Li x V 2 -y My (PO 4 ) z , where M is a metal element having an atomic number of 11 or more. For example, Fe, Co, Mn, Cu, Zn, It is at least one selected from the group consisting of Al, Sn, B, Ga, Cr, V, Ti, Mg, Ca, Sr, and Zr, and satisfies 1 ≦ x ≦ 3, 0 ≦ y2, and 2 ≦ z ≦ 3 Material to be included. For example, Li 3 V 2 (PO 4 ) 3 .

本発明によれば、カーボンを被覆したリン酸バナジウムリチウム及びリチウムニッケル複合酸化物を正極の活物質に含み、且つリチウムイオン脱挿入可能なカーボン系活物質を負極の活物質に含む。ここで、負極のリチウム脱マージンをこれまで以上に多く設定している。具体的には、単位面積当たりの負極初度充電容量をx[mAh/cm2]、単位面積当たりの正極初度充電容量をy[mAh/cm2]としたときのxとyとの関係が、0.6≦y/x≦0.92の関係を満たすように負極のリチウム脱マージンを大きく設定した。 According to the present invention, lithium vanadium phosphate and lithium nickel composite oxide coated with carbon are included in the positive electrode active material, and a carbon-based active material capable of lithium ion desorption is included in the negative electrode active material. Here, the lithium margin of the negative electrode is set more than ever. Specifically, the relationship between x and y when the negative electrode initial charge capacity per unit area is x [mAh / cm 2 ] and the positive electrode initial charge capacity per unit area is y [mAh / cm 2 ], The lithium demargin of the negative electrode was set large so as to satisfy the relationship of 0.6 ≦ y / x ≦ 0.92.

したがって、導電性金属異物等の突き刺しによる内部短絡等が発生した場合でも、負極からのリチウムイオンの供与性を高め、セルの異常発熱や発火を引き起こさない安全で且つサイクル特性の良好な非水電解質二次電池を実現している。   Therefore, even when an internal short circuit or the like due to the piercing of a conductive metal foreign matter or the like occurs, the non-aqueous electrolyte has a safe and good cycle characteristic that improves the donation of lithium ions from the negative electrode and does not cause abnormal heat generation or ignition of the cell. A secondary battery is realized.

なお、本発明の非水電解質二次電池は、正極の活物質としてカーボンを被覆したリン酸バナジウムリチウム及びリチウムニッケル複合酸化物を使用しており、正極活物質に含まれるリチウムニッケル複合酸化物を所定の割合とすることにより、高出力と高い安全性を有すると共に、高容量で良好な充放電サイクル特性を実現している。   The nonaqueous electrolyte secondary battery of the present invention uses lithium vanadium phosphate and lithium nickel composite oxide coated with carbon as the positive electrode active material, and the lithium nickel composite oxide contained in the positive electrode active material is used. By setting it to a predetermined ratio, it has high output and high safety, and realizes good charge / discharge cycle characteristics with high capacity.

本発明の非水電解質二次電池(リチウムイオン二次電池)の実施形態の一例を示す概略断面図である。It is a schematic sectional drawing which shows an example of embodiment of the nonaqueous electrolyte secondary battery (lithium ion secondary battery) of this invention. 本発明の非水電解質二次電池(リチウムイオン二次電池)の実施形態の別の一例を示す概略断面図である。It is a schematic sectional drawing which shows another example of embodiment of the nonaqueous electrolyte secondary battery (lithium ion secondary battery) of this invention.

以下、本発明の実施の形態を詳細に説明する。本発明は、非水電解質二次電池に関する技術である。非水電解質二次電池としては、リチウムイオン二次電池等が挙げられる。後述するように、本発明の非水電解質二次電池において、正極及び負極以外の構成は、特に制限されず、本発明の効果を阻害しない限り、従来公知の技術を適宜組み合わせて実施することができる。   Hereinafter, embodiments of the present invention will be described in detail. The present invention is a technique related to a non-aqueous electrolyte secondary battery. Examples of the non-aqueous electrolyte secondary battery include a lithium ion secondary battery. As will be described later, in the nonaqueous electrolyte secondary battery of the present invention, the configuration other than the positive electrode and the negative electrode is not particularly limited, and may be carried out by appropriately combining conventionally known techniques as long as the effects of the present invention are not impaired. it can.

本実施形態の非水電解質二次電池は、正極活物質を含む正極合材層を備えた正極を有し、正極活物質としてナシコン型のリン酸バナジウムリチウム、すなわちLi32(PO43とリチウムニッケル複合酸化物とを用いている。なお、本発明におけるナシコン型のリン酸バナジウムリチウムとしては、代表例としてLi32(PO43を挙げて説明するが、一般式Lix2-yy(PO4zで表され、Mが原子番号11以上の金属元素であって、例えば、Fe、Co、Mn、Cu、Zn、Al、Sn、B、Ga、Cr、V、Ti、Mg、Ca、Sr、Zrからなる群より選ばれる一種以上であり、且つ1≦x≦3、0≦y<2、2≦z≦3を満足する材料であっても本発明の同様の効果を得ることができる。 The nonaqueous electrolyte secondary battery of the present embodiment has a positive electrode provided with a positive electrode mixture layer containing a positive electrode active material, and a Nasicon-type lithium vanadium phosphate, that is, Li 3 V 2 (PO 4 ) as the positive electrode active material. 3 and lithium nickel composite oxide are used. In addition, as a NASICON type lithium vanadium phosphate in the present invention, Li 3 V 2 (PO 4 ) 3 will be described as a representative example, but the general formula Li x V 2 -y My (PO 4 ) z M is a metal element having an atomic number of 11 or more, for example, Fe, Co, Mn, Cu, Zn, Al, Sn, B, Ga, Cr, V, Ti, Mg, Ca, Sr, Zr The same effect of the present invention can be obtained even if the material is at least one selected from the group consisting of 1 ≦ x ≦ 3, 0 ≦ y <2, and 2 ≦ z ≦ 3.

[Li32(PO43
本発明において、Li32(PO43は、どのような方法で製造されても良く、特に制限されない。例えば、LiOH、LiOH・H2O等のリチウム源、V25、V23等のバナジウム源、及びNH42PO4、(NH42HPO4等のリン酸源等を混合し、反応、焼成する等により製造できる。Li32(PO43は、通常、焼成物を粉砕等した粒子状の形態で得られる。
[Li 3 V 2 (PO 4 ) 3 ]
In the present invention, Li 3 V 2 (PO 4 ) 3 may be produced by any method and is not particularly limited. For example, lithium sources such as LiOH and LiOH.H 2 O, vanadium sources such as V 2 O 5 and V 2 O 3 , and phosphoric acid sources such as NH 4 H 2 PO 4 and (NH 4 ) 2 HPO 4 It can be produced by mixing, reacting, firing and the like. Li 3 V 2 (PO 4 ) 3 is usually obtained in the form of particles obtained by pulverizing the fired product.

また、Li32(PO43は、それ自体では電子伝導性が低いため、その表面に導電性カーボン被膜加工を行う必要がある。これによりLi32(PO43の電子伝導性を向上することができる。導電性カーボンの被膜量はC原子換算で0.1〜20質量%であることが好ましい。 Moreover, since Li 3 V 2 (PO 4 ) 3 itself has low electronic conductivity, it is necessary to perform conductive carbon coating on the surface thereof. Thereby, the electronic conductivity of Li 3 V 2 (PO 4 ) 3 can be improved. The coating amount of the conductive carbon is preferably 0.1 to 20% by mass in terms of C atoms.

導電性カーボン被膜加工は、公知の方法で行うことができる。例えば、カーボン被膜材料として、クエン酸、アスコルビン酸、ポリエチレングリコール、ショ糖、メタノール、プロペン、カーボンブラック、ケッチェンブラック等を用い、上述のLi32(PO43製造の反応時や焼成時に混合すること等によって表面に導電性カーボン被膜を形成させることができる。 The conductive carbon film processing can be performed by a known method. For example, citric acid, ascorbic acid, polyethylene glycol, sucrose, methanol, propene, carbon black, ketjen black, etc. are used as the carbon coating material, and during the above Li 3 V 2 (PO 4 ) 3 production reaction or firing A conductive carbon film can be formed on the surface by mixing at times.

Li32(PO43粒子の粒度には特に制限は無く、所望の粒度のものを使用することができる。粒度はLi32(PO43の安定性や密度に影響するため、Li32(PO43の2次粒子の粒度分布におけるD50が0.5〜25μmであることが好ましい。上記D50が0.5μm未満の場合は、電解液との接触面積が増加することからLi32(PO43の安定性が低下する場合があり、25μmを超える場合は密度低下のため出力が低下する場合がある。上記の範囲であれば、より安定性が高く高出力の蓄電デバイスとすることができる。Li32(PO43の2次粒子の粒度分布におけるD50は1〜10μmであることが更に好ましく、3〜5μmであることが特に好ましい。なお、この2次粒子の粒度分布におけるD50は、レーザー回折(光散乱法)方式による粒度分布測定装置を用いて測定した値とする。 The particle size of the Li 3 V 2 (PO 4 ) 3 particles is not particularly limited, and those having a desired particle size can be used. Since the particle size which affects the stability and density of the Li 3 V 2 (PO 4) 3, Li 3 V 2 (PO 4) D 50 in the particle size distribution of secondary particles of 3 to be 0.5~25μm preferable. When the D 50 is less than 0.5 μm, the contact area with the electrolytic solution increases, so the stability of Li 3 V 2 (PO 4 ) 3 may decrease, and when it exceeds 25 μm, the density decreases. Therefore, the output may decrease. If it is said range, it can be set as an electrical storage device with higher stability and high output. D 50 in the particle size distribution of the secondary particles of Li 3 V 2 (PO 4 ) 3 is more preferably 1 to 10 μm, and particularly preferably 3 to 5 μm. Note that D 50 in the particle size distribution of the secondary particles is a value measured using a particle size distribution measuring apparatus by a laser diffraction (light scattering method) method.

[リチウムニッケル複合酸化物]
本発明では種々のリチウムニッケル複合酸化物を用いることができる。リチウムニッケル複合酸化物のNi元素の構成比率はリチウムニッケル複合酸化物のプロトン吸着性に影響する。本発明においてNi元素は、リチウム原子1モルに対して0.3モル以上、0.8モル以下含まれていることが好ましく、0.5モル以上、0.8モル以下含まれていることが更に好ましい。Ni元素の構成比率が低すぎると、Li32(PO43からのバナジウムの溶出の抑制効果が十分に発揮されない場合がある。上記範囲内であれば、Ni元素の構成比率が高いほど、Li32(PO43からのバナジウム溶出の抑制効果が向上する。特に、Ni元素がリチウム原子1モルに対して0.5モル以上であると、そのバナジウム溶出抑制効果により、容量維持率が格段に向上する。
[Lithium nickel composite oxide]
In the present invention, various lithium nickel composite oxides can be used. The composition ratio of Ni element in the lithium nickel composite oxide affects the proton adsorptivity of the lithium nickel composite oxide. In the present invention, Ni element is preferably contained in an amount of 0.3 mol or more and 0.8 mol or less, and 0.5 mol or more and 0.8 mol or less, per mol of lithium atom. Further preferred. If the composition ratio of Ni element is too low, the effect of suppressing the elution of vanadium from Li 3 V 2 (PO 4 ) 3 may not be sufficiently exhibited. Within the above range, the higher the composition ratio of Ni element, it improves the effect of suppressing the vanadium elution from Li 3 V 2 (PO 4) 3. In particular, when the Ni element is 0.5 mol or more with respect to 1 mol of lithium atoms, the capacity retention rate is remarkably improved due to the vanadium elution suppression effect.

また、本発明のリチウムニッケル複合酸化物には、Niサイトに、原子番号11以上のNiとは異なる金属元素が置換されていてもよい。原子番号11以上のNiとは異なる金属元素は、遷移元素から選択されることが好ましい。遷移元素はNiと同様に複数の酸化数をとることができるため、リチウムニッケル複合酸化物において、その酸化還元電位の範囲を利用することができ、高容量特性を維持できる。原子番号11以上のNiとは異なる金属元素とは、例えば、Co、Mn、Al及びMgであり、好ましくは、Co、Mnである。   In the lithium nickel composite oxide of the present invention, a metal element different from Ni having an atomic number of 11 or more may be substituted at the Ni site. The metal element different from Ni having atomic number 11 or more is preferably selected from transition elements. Since the transition element can take a plurality of oxidation numbers like Ni, in the lithium nickel composite oxide, the range of the oxidation-reduction potential can be used, and high capacity characteristics can be maintained. Examples of the metal element different from Ni having an atomic number of 11 or more are Co, Mn, Al and Mg, and preferably Co and Mn.

また、本発明のリチウムニッケル複合酸化物は、例えば、一般式LixNi1-yM’y2(但し、0.8≦x≦1.2、0.2≦y≦0.7であり、M’がFe、Co、Mn、Cu、Zn、Al、Sn、B、Ga、Cr、V、Ti、Mg、Ca、Srからなる群より選ばれる一種以上である。)で表される化合物であることが好ましい。更に、0.2≦y≦0.5であることが好ましい。 Moreover, the lithium nickel composite oxide of the present invention has, for example, a general formula Li x Ni 1-y M ′ y O 2 (where 0.8 ≦ x ≦ 1.2, 0.2 ≦ y ≦ 0.7 M ′ is one or more selected from the group consisting of Fe, Co, Mn, Cu, Zn, Al, Sn, B, Ga, Cr, V, Ti, Mg, Ca, and Sr. A compound is preferred. Furthermore, it is preferable that 0.2 ≦ y ≦ 0.5.

リチウムニッケル複合酸化物は、どのような方法で製造されてもよく、特に制限されない。例えば、固相反応法、共沈法又はゾルゲル法等により合成したNi含有前駆体とリチウム化合物とを所望の化学量論比となるように混合し、空気雰囲気下で焼成する等により製造できる。   The lithium nickel composite oxide may be produced by any method and is not particularly limited. For example, it can be produced by mixing a Ni-containing precursor synthesized by a solid phase reaction method, a coprecipitation method, a sol-gel method or the like with a lithium compound so as to have a desired stoichiometric ratio, and firing in an air atmosphere.

リチウムニッケル複合酸化物は、通常、焼成物を粉砕等した粒子状の形態で得られる、その粒径には特に制限は無く、所望の粒径のものを使用することができる。粒径はリチウムニッケル複合酸化物の安定性や密度に影響するため、粒子の平均粒径は、0.5〜25μmであることが好ましい。平均粒径が、0.5μm未満の場合は、電解液との接触面積が増加することからリチウムニッケル複合酸化物の安定性が低下する場合があり、25μmを超える場合は密度低下のため出力が低下する場合がある。上記の範囲であれば、より安定性が高く高出力の蓄電デバイスとすることができる。リチウムニッケル複合酸化物の粒子の平均粒径は、1〜25μmが更に好ましく、5〜20μmが特に好ましい。なお、この粒子の平均粒径はレーザー回折(光散乱法)方式による粒度分布測定装置を用いて測定した値とする。   The lithium nickel composite oxide is usually obtained in a particulate form obtained by pulverizing the fired product, and the particle size is not particularly limited, and those having a desired particle size can be used. Since the particle size affects the stability and density of the lithium nickel composite oxide, the average particle size of the particles is preferably 0.5 to 25 μm. When the average particle size is less than 0.5 μm, the contact area with the electrolytic solution increases, so the stability of the lithium nickel composite oxide may decrease. When the average particle size exceeds 25 μm, the output decreases due to the decrease in density. May decrease. If it is said range, it can be set as an electrical storage device with higher stability and high output. The average particle diameter of the lithium nickel composite oxide particles is more preferably 1 to 25 μm, and particularly preferably 5 to 20 μm. In addition, let the average particle diameter of this particle | grain be the value measured using the particle size distribution measuring apparatus by a laser diffraction (light scattering method) system.

[正極]
本発明における正極は、正極活物質として上述のカーボンを被覆したLi32(PO43及びリチウムニッケル複合酸化物を含んでいれば良く、それ以外は公知の材料を用いて作製することができる。具体的には、例えば以下のように作製する。
[Positive electrode]
The positive electrode in the present invention only needs to contain Li 3 V 2 (PO 4 ) 3 and lithium nickel composite oxide coated with the above-mentioned carbon as a positive electrode active material, and is manufactured using other known materials. Can do. Specifically, for example, it is manufactured as follows.

上記正極活物質、結合剤、導電助剤を含む混合物を溶媒に分散させた正極スラリーを、正極集電体上に塗布、乾燥を含む工程により正極合材層を形成する。乾燥工程後にプレス加圧等を行っても良い。これにより正極合材層が均一且つ強固に集電体に圧着される。正極合材層の厚みは10〜200μm、好ましくは20〜100μmである。   A positive electrode mixture layer is formed by a process including coating and drying a positive electrode slurry in which a mixture containing the positive electrode active material, the binder, and the conductive additive is dispersed in a solvent. You may press-press etc. after a drying process. As a result, the positive electrode mixture layer is uniformly and firmly pressed onto the current collector. The thickness of the positive electrode mixture layer is 10 to 200 μm, preferably 20 to 100 μm.

正極合材層の形成に用いる結合剤としては、例えばポリフッ化ビニリデン等の含フッ素系樹脂、アクリル系バインダ、SBR等のゴム系バインダ、ポリプロピレン、ポリエチレン等の熱可塑性樹脂、カルボキシメチルセルロース等が使用できる。結合剤は、本発明の蓄電デバイスに用いられる非水電解液に対して化学的、電気化学的に安定な含フッ素系樹脂、熱可塑性樹脂が好ましく、特に含フッ素系樹脂が好ましい。含フッ素系樹脂としてはポリフッ化ビニリデンの他、ポリテトラフルオロエチレン、フッ化ビニリデン−3フッ化エチレン共重合体、エチレン−4フッ化エチレン共重合体及びプロピレン−4フッ化エチレン共重合体等が挙げられる。結合剤の配合量は、上記正極活物質に対して0.5〜20質量%が好ましい。   As the binder used for forming the positive electrode mixture layer, for example, a fluorine-containing resin such as polyvinylidene fluoride, an acrylic binder, a rubber binder such as SBR, a thermoplastic resin such as polypropylene or polyethylene, carboxymethylcellulose, or the like can be used. . The binder is preferably a fluorine-containing resin or a thermoplastic resin that is chemically and electrochemically stable with respect to the non-aqueous electrolyte used in the electricity storage device of the present invention, and particularly preferably a fluorine-containing resin. As the fluorine-containing resin, in addition to polyvinylidene fluoride, polytetrafluoroethylene, vinylidene fluoride-3 fluoroethylene copolymer, ethylene-4 fluoroethylene copolymer, propylene-4 fluoroethylene copolymer, etc. Can be mentioned. The blending amount of the binder is preferably 0.5 to 20% by mass with respect to the positive electrode active material.

正極合材層の形成に用いる導電助剤としては、例えばケッチェンブラック等の導電性カーボン、銅、鉄、銀、ニッケル、パラジウム、金、白金、インジウム及びタングステン等の金属、酸化インジウム及び酸化スズ等の導電性金属酸化物等が使用できる。導電材の配合量は、上記正極活物質に対して1〜30質量%が好ましい。   Examples of the conductive assistant used for forming the positive electrode mixture layer include conductive carbon such as ketjen black, metals such as copper, iron, silver, nickel, palladium, gold, platinum, indium and tungsten, indium oxide and tin oxide. Conductive metal oxides such as can be used. As for the compounding quantity of an electrically conductive material, 1-30 mass% is preferable with respect to the said positive electrode active material.

正極合材層の形成に用いる溶媒としては、水、イソプロピルアルコール、N−メチルピロリドン、ジメチルホルムアミド等が使用できる。   As a solvent used for forming the positive electrode mixture layer, water, isopropyl alcohol, N-methylpyrrolidone, dimethylformamide, or the like can be used.

正極集電体は正極合材層と接する面が導電性を示す導電性基体であれば良く、例えば、金属、導電性金属酸化物、導電性カーボン等の導電性材料で形成された導電性基体や、非導電性の基体本体を上記の導電性材料で被覆したものが使用できる。導電性材料としては、銅、金、アルミニウムもしくはそれらの合金又は導電性カーボンが好ましい。正極集電体は、上記材料のエキスパンドメタル、パンチングメタル、箔、網、発泡体等を用いることができる。多孔質体の場合の貫通孔の形状や個数等は特に制限はなく、リチウムイオンの移動を阻害しない範囲で適宜設定できる。   The positive electrode current collector need only be a conductive substrate whose surface in contact with the positive electrode mixture layer exhibits conductivity. For example, a conductive substrate formed of a conductive material such as metal, conductive metal oxide, or conductive carbon. Alternatively, a non-conductive base body covered with the above conductive material can be used. As the conductive material, copper, gold, aluminum, an alloy thereof, or conductive carbon is preferable. As the positive electrode current collector, an expanded metal, a punching metal, a foil, a net, a foam, or the like of the above materials can be used. The shape and number of through holes in the case of a porous body are not particularly limited, and can be appropriately set within a range that does not inhibit the movement of lithium ions.

本発明において、正極の活物質に含まれるリチウムニッケル複合酸化物の割合は、5から95質量%の範囲である。リチウムニッケル複合酸化物の含有率が低過ぎると、Li32(PO43からのバナジウムの溶出の抑制効果が十分に発揮されず、良好な充放電サイクル特性が得られない。また、高容量が得られない。逆に高過ぎるとLi32(PO43からバナジウムの溶出を抑制することができても、蓄電デバイスの充放電サイクル特性が十分に向上しない場合がある。これは、リチウムニッケル複合酸化物自体の安定性が低いことにより劣化するためであると考えられる。上述の範囲であれば、高容量で優れたサイクル特性を得ることができる。 In the present invention, the proportion of the lithium nickel composite oxide contained in the positive electrode active material is in the range of 5 to 95% by mass. If the content of the lithium nickel composite oxide is too low, the effect of suppressing the elution of vanadium from Li 3 V 2 (PO 4 ) 3 is not sufficiently exhibited, and good charge / discharge cycle characteristics cannot be obtained. Moreover, a high capacity cannot be obtained. On the other hand, if too high, elution of vanadium from Li 3 V 2 (PO 4 ) 3 can be suppressed, but the charge / discharge cycle characteristics of the electricity storage device may not be sufficiently improved. This is considered to be because the lithium nickel composite oxide itself deteriorates due to low stability. If it is the above-mentioned range, it is possible to obtain excellent cycle characteristics with a high capacity.

[負極]
本発明において負極は、リチウムイオン脱挿入可能なカーボン系活物質を含む。例えば、リチウムインターカレーション炭素材料が挙げられる。この負極活物質及び結合剤を含む混合物を溶媒に分散させた負極スラリーを、負極集電体上に塗布、乾燥等することにより負極合材層を形成する。なお、結合剤、溶媒及び集電体は上述の正極の場合と同様なものが使用できる。
[Negative electrode]
In the present invention, the negative electrode contains a carbon-based active material capable of lithium ion desorption. An example is a lithium intercalation carbon material. A negative electrode slurry in which a mixture containing the negative electrode active material and a binder is dispersed in a solvent is applied onto a negative electrode current collector, dried, and the like, thereby forming a negative electrode mixture layer. Note that the same binder, solvent, and current collector as in the case of the positive electrode described above can be used.

リチウムインターカレーション炭素材料としては、例えば、黒鉛、難黒鉛化炭素材料等の炭素系材料、ポリアセン物質等が挙げられる。ポリアセン系物質は、例えばポリアセン系骨格を有する不溶且つ不融性のPAS等である。なお、これらのリチウムインターカレーション炭素材料は、いずれもリチウムイオンを可逆的にドープ可能な物質である。負極合材層の厚みは一般に10〜200μm、好ましくは20〜100μmである。   Examples of the lithium intercalation carbon material include carbon materials such as graphite and non-graphitizable carbon materials, polyacene substances, and the like. Examples of the polyacene material include insoluble and infusible PAS having a polyacene skeleton. These lithium intercalation carbon materials are substances that can be reversibly doped with lithium ions. The thickness of the negative electrode mixture layer is generally 10 to 200 μm, preferably 20 to 100 μm.

更に、本発明おいては、負極及び正極合材層の塗工量は、単位面積当たりの負極初度充電容量をx[mAh/cm2]、単位面積当たりの正極初度充電容量をy[mAh/cm2]としたときのxとyとの関係が、通常、正負極の容量バランスやエネルギー密度の観点から、0.95<y/x<1となるように設計されているのに対して、0.6≦y/x≦0.92となるようにした。ここで、負極の塗工量とx、及び正極の塗工量とyとの関係は、それぞれ塗工量を倍にするとx又はyも倍となる線形の関係にある。 Furthermore, in the present invention, the coating amount of the negative electrode and the positive electrode mixture layer is such that the negative electrode initial charge capacity per unit area is x [mAh / cm 2 ] and the positive electrode initial charge capacity per unit area is y [mAh / The relationship between x and y when cm 2 ] is normally designed so that 0.95 <y / x <1 from the viewpoint of capacity balance and energy density of positive and negative electrodes 0.6 ≦ y / x ≦ 0.92. Here, the relationship between the coating amount of the negative electrode and x, and the coating amount of the positive electrode and y has a linear relationship in which x or y also doubles when the coating amount is doubled.

[非水電解液]
本発明における非水電解液は、特に制限はなく、公知の材料を使用できる。例えば、高電圧でも電気分解を起こさないという点、リチウムイオンが安定に存在できるという点から、一般的なリチウム塩を電解質とし、これを有機溶媒に溶解した電解液を使用できる。
[Non-aqueous electrolyte]
There is no restriction | limiting in particular in the non-aqueous electrolyte in this invention, A well-known material can be used. For example, an electrolytic solution in which a general lithium salt is used as an electrolyte and is dissolved in an organic solvent can be used from the viewpoint that electrolysis does not occur even at a high voltage and that lithium ions can exist stably.

電解質としては、例えば、CF3SO3Li、C49SO8Li、(CF3SO22NLi、(CF3SO23CLi、LiBF4、LiPF6、LiClO4等又はこれらの2種以上の混合物が挙げられる。 Examples of the electrolyte include CF 3 SO 3 Li, C 4 F 9 SO 8 Li, (CF 3 SO 2 ) 2 NLi, (CF 3 SO 2 ) 3 CLi, LiBF 4 , LiPF 6 , LiClO 4, etc. The mixture of 2 or more types is mentioned.

有機溶媒としては、例えば、プロピレンカーボネート、エチレンカーボネート、ブチレンカーボネート、ジメチルカーボネート、ジエチルカーボネート、エチルメチルカーボネート、ビニルカーボネート、トリフルオロメチルプロピレンカーボネート、1,2−ジメトキシエタン、1,2−ジエトキシエタン、γ−ブチロラクトン、テトラヒドロフラン、1,3−ジオキソラン、4-メチル−1,3−ジオキソラン、ジエチルエーテル、スルホラン、メチルスルホラン、アセトニトリル、プロピオトリル等又はこれらの2種以上の混合溶媒が挙げられる。   Examples of the organic solvent include propylene carbonate, ethylene carbonate, butylene carbonate, dimethyl carbonate, diethyl carbonate, ethyl methyl carbonate, vinyl carbonate, trifluoromethyl propylene carbonate, 1,2-dimethoxyethane, 1,2-diethoxyethane, Examples thereof include γ-butyrolactone, tetrahydrofuran, 1,3-dioxolane, 4-methyl-1,3-dioxolane, diethyl ether, sulfolane, methyl sulfolane, acetonitrile, propiotolyl and the like, or a mixed solvent of two or more thereof.

非水電解液中の電解質濃度は0.1〜5.0mol/Lが好ましく、0.5〜3.0mol/Lが更に好ましい。   The electrolyte concentration in the non-aqueous electrolyte is preferably 0.1 to 5.0 mol / L, and more preferably 0.5 to 3.0 mol / L.

非水電解液は液状でも良く、可塑剤やポリマー等を混合し、固体電解質又はポリマーゲル電解質としたものでも良い。   The non-aqueous electrolyte may be liquid, or may be a solid electrolyte or polymer gel electrolyte mixed with a plasticizer or a polymer.

[セパレータ]
本発明で使用するセパレータは、特に制限はなく、公知のセパレータを使用できる。例えば、電解液、正極活物質、負極活物質に対して耐久性があり、連通気孔を有する電子伝導性の無い多孔質体等を好ましく使用できる。このような多孔質体として例えば、織布、不織布、合成樹脂性微多孔膜、ガラス繊維などが挙げられる。合成樹脂性の微多孔膜が好ましく用いられ、特にポリエチレンやポリプロピレン等のポリオレフィン製微多孔膜が、厚さ、膜強度、膜抵抗の面で好ましい。
[Separator]
There is no restriction | limiting in particular in the separator used by this invention, A well-known separator can be used. For example, a porous body having durability against an electrolytic solution, a positive electrode active material, and a negative electrode active material and having continuous air holes and having no electronic conductivity can be preferably used. Examples of such a porous body include woven fabric, non-woven fabric, synthetic resin microporous membrane, and glass fiber. A synthetic resin microporous membrane is preferably used, and a polyolefin microporous membrane such as polyethylene or polypropylene is particularly preferable in terms of thickness, membrane strength, and membrane resistance.

以下に本発明の非水電解質二次電池の実施形態の一例として、リチウムイオン二次電池の例を、図面を参照しながら説明する。   Hereinafter, as an example of an embodiment of the nonaqueous electrolyte secondary battery of the present invention, an example of a lithium ion secondary battery will be described with reference to the drawings.

図1は、本発明に係るリチウムイオン二次電池の実施形態の一例を示す概略断面図である。図示のように、リチウムイオン二次電池20は、正極21と、負極22とがセパレータ23を介して対向配置されて構成されている。   FIG. 1 is a schematic cross-sectional view showing an example of an embodiment of a lithium ion secondary battery according to the present invention. As shown in the figure, the lithium ion secondary battery 20 is configured such that a positive electrode 21 and a negative electrode 22 are arranged to face each other with a separator 23 interposed therebetween.

正極21は、本発明の正極活物質を含む正極合材層21aと、正極集電体21bとから構成されている。正極合材層21aは、正極集電体21bのセパレータ23側の面に形成されている。負極22は、負極合材層22aと、負極集電体22bとから構成されている。負極合材層22aは、負極集電体22bのセパレータ23側の面に形成されている。これら正極21、負極22、セパレータ23は、図示しない外装容器に封入されており、外装容器内には非水電解液が充填されている。外装材としては例えば電池缶やラミネートフィルム等が挙げられる。また、正極集電体21bと負極集電体22bとには、必要に応じて、それぞれ外部端子接続用の図示しないリードが接続されている。   The positive electrode 21 includes a positive electrode mixture layer 21a containing a positive electrode active material of the present invention and a positive electrode current collector 21b. The positive electrode mixture layer 21a is formed on the separator 23 side surface of the positive electrode current collector 21b. The negative electrode 22 includes a negative electrode mixture layer 22a and a negative electrode current collector 22b. The negative electrode mixture layer 22a is formed on the separator 23 side surface of the negative electrode current collector 22b. The positive electrode 21, the negative electrode 22, and the separator 23 are sealed in an outer container (not shown), and the outer container is filled with a non-aqueous electrolyte. Examples of the exterior material include a battery can and a laminate film. Further, leads (not shown) for connecting external terminals are respectively connected to the positive electrode current collector 21b and the negative electrode current collector 22b as necessary.

次に、図2は、本発明に係るリチウムイオン二次電池の実施形態の別の一例を示す概略断面図である。図示のように、リチウムイオン二次電池30は、正極31と負極32とが、セパレータ33を介して交互に複数積層された電極ユニット34を備えている。正極31は、正極合材層31aが、正極集電体31bの両面に設けられて構成されている。負極32は、負極合材層32aが負極集電体32bの両面に設けられて構成されている(ただし、最上部および最下部の負極32については、負極合材層32aは片面のみ)。また、正極集電体31bは図示しないが突出部分を有しており、複数の正極集電体31bの各突出部分はそれぞれ重ね合わされ、その重ね合わされた部分にリード36が溶接されている。負極集電体32bも同様に突出部分を有しており、複数の負極集電体32bの各突出部分が重ね合わされた部分にリード37が溶接されている。リチウムイオン二次電池30は、図示しないラミネートフィルム等の外装容器内に電極ユニット34と非水電解液が封入されて構成されている。リード36,37は外部機器との接続のため、外装容器の外部に露出される。   Next, FIG. 2 is a schematic sectional view showing another example of the embodiment of the lithium ion secondary battery according to the present invention. As shown in the figure, the lithium ion secondary battery 30 includes an electrode unit 34 in which a plurality of positive electrodes 31 and negative electrodes 32 are alternately stacked via separators 33. The positive electrode 31 is configured by providing a positive electrode mixture layer 31a on both surfaces of a positive electrode current collector 31b. The negative electrode 32 is configured such that the negative electrode mixture layer 32a is provided on both surfaces of the negative electrode current collector 32b (however, for the uppermost and lowermost negative electrodes 32, the negative electrode mixture layer 32a is only on one side). Further, although not shown, the positive electrode current collector 31b has a protruding portion, the protruding portions of the plurality of positive electrode current collectors 31b are overlapped, and the lead 36 is welded to the overlapped portion. Similarly, the negative electrode current collector 32b has a protruding portion, and a lead 37 is welded to a portion where the protruding portions of the plurality of negative electrode current collectors 32b are overlapped. The lithium ion secondary battery 30 is configured by enclosing an electrode unit 34 and a non-aqueous electrolyte in an exterior container such as a laminate film (not shown). The leads 36 and 37 are exposed to the outside of the outer container for connection with an external device.

なお、リチウムイオン二次電池30は、外装容器内に、正極、負極、又は正負極双方にリチウムイオンをプレドープする為のリチウム極を備えていてもよい。その場合には、リチウムイオンが移動し易くするため、正極集電体31bや負極集電体32bに電極ユニット34の積層方向に貫通する貫通孔が設けられる。   Note that the lithium ion secondary battery 30 may include a lithium electrode for pre-doping lithium ions in the positive electrode, the negative electrode, or both the positive and negative electrodes in the outer container. In that case, in order to facilitate movement of lithium ions, a through-hole penetrating in the stacking direction of the electrode unit 34 is provided in the positive electrode current collector 31b and the negative electrode current collector 32b.

また、リチウムイオン二次電池30は、最上部および最下部に負極を配置させたが、これに限定されず、最上部および最下部に正極を配置させる構成でもよい。   Moreover, although the lithium ion secondary battery 30 has the negative electrode disposed at the uppermost part and the lowermost part, the present invention is not limited to this, and the positive electrode may be disposed at the uppermost part and the lowermost part.

以下、本発明を実施例により説明する。   Hereinafter, the present invention will be described with reference to examples.

(実施例1)
(1)正極の作製
以下の正極合材層用材料:
第一活物質(Li32(PO43) ; 30質量部
第二活物質(LiNi0.8Co0.1Mn0.12) ; 60質量部
結合剤(ポリフッ化ビニリデン(PVdF)) ; 5質量部
導電材(カーボンブラック) ; 5質量部
溶媒(N−メチル2−ピロリドン(NMP)) ;100質量部
を混合し、正極スラリーを得た。正極スラリーをアルミニウム箔(厚み30μm)の正極集電体に塗布、乾燥し、正極合材層を正極集電体上に形成した。正極合材層の塗工量は(片面当たり)14mg/cm2であった。10×10mmの未塗工部分をリード接続用のタブとして残しつつ、塗工部分(正極合材層形成部分)を50×50mmに裁断した。なお、Li32(PO43はカーボンをC原子換算で1.4質量%被覆したものを用いた。
Example 1
(1) Production of positive electrode The following positive electrode mixture layer material:
First active material (Li 3 V 2 (PO 4 ) 3 ); 30 parts by mass Second active material (LiNi 0.8 Co 0.1 Mn 0.1 O 2 ); 60 parts by mass Binder (polyvinylidene fluoride (PVdF)); 5 parts by mass Part: Conductive material (carbon black); 5 parts by mass Solvent (N-methyl 2-pyrrolidone (NMP)); 100 parts by mass were mixed to obtain a positive electrode slurry. The positive electrode slurry was applied to a positive electrode current collector made of aluminum foil (thickness 30 μm) and dried to form a positive electrode mixture layer on the positive electrode current collector. The coating amount of the positive electrode mixture layer was 14 mg / cm 2 (per one side). The coated portion (positive electrode mixture layer forming portion) was cut to 50 × 50 mm while leaving the uncoated portion of 10 × 10 mm as a tab for lead connection. Incidentally, Li 3 V 2 (PO 4 ) 3 was used as coated 1.4 wt% of carbon in C atoms terms.

(2)負極の作製
以下の負極合材層用材料:
活物質(グラファイト) ; 95質量部
結合剤(PVdF) ; 5質量部
溶媒(NMP) ;150質量部
を混合し、負極スラリーを得た。負極スラリーを銅箔(厚み10μm)の負極集電体に塗布、乾燥し、負極合材層を負極集電体上に形成した。負極合材層の塗工量は(片面当たり)7.2mg/cm2であった。これは、単位面積当たりの負極初度充電容量をx[mAh/cm2]、単位面積当たりの正極初度充電容量をy[mAh/cm2]としたときのxとyの関係がy/x=0.9となるようにした。そして、10×10mmの未塗工部分をリード接続用のタブとして残しつつ、塗工部分(負極合材層形成部分)を52×52mmに裁断した。
(2) Production of negative electrode The following negative electrode composite layer material:
Active material (graphite); 95 parts by mass Binder (PVdF); 5 parts by mass Solvent (NMP); 150 parts by mass were mixed to obtain a negative electrode slurry. The negative electrode slurry was applied to a negative electrode current collector of copper foil (thickness 10 μm) and dried to form a negative electrode mixture layer on the negative electrode current collector. The coating amount of the negative electrode mixture layer was 7.2 mg / cm 2 (per one side). This is because the relationship between x and y when the negative electrode initial charge capacity per unit area is x [mAh / cm 2 ] and the positive electrode initial charge capacity per unit area is y [mAh / cm 2 ] is y / x = It was set to 0.9. Then, the coated portion (negative electrode mixture layer forming portion) was cut into 52 × 52 mm while leaving the uncoated portion of 10 × 10 mm as a tab for lead connection.

(3)電池の作製
上述のように作製した正極19枚と、負極20枚とを用いて、図2の実施形態で示したようなリチウムイオン二次電池を作製した。具体的には、正極及び負極をセパレータを介して積層し、積層体の周囲をテープで固定した。各正極集電体のタブを重ねてアルミニウム金属リードを溶接した。同様に各負極集電体のタブを重ねてニッケル金属リードを溶接した。これらをアルミラミネート外装材に封入し、正極リードと負極リードを外装材外側に出して、電解液封入口を残して密閉融着した。電解液封入口より電解液を注液し、真空含浸にて電極内部に電解液を浸透させた後、ラミネートを真空封止した。
(3) Production of Battery A lithium ion secondary battery as shown in the embodiment of FIG. 2 was produced using 19 positive electrodes and 20 negative electrodes produced as described above. Specifically, the positive electrode and the negative electrode were laminated via a separator, and the periphery of the laminate was fixed with a tape. Aluminum metal leads were welded with the tabs of each positive electrode current collector overlapped. Similarly, the nickel metal lead was welded with the tabs of the respective negative electrode current collectors overlapped. These were encapsulated in an aluminum laminate exterior material, and the positive electrode lead and the negative electrode lead were taken out of the exterior material, and hermetically sealed, leaving the electrolyte solution enclosing port. The electrolyte was poured from the electrolyte filling port, and the electrolyte was infiltrated into the electrode by vacuum impregnation, and then the laminate was vacuum sealed.

(4)充放電試験
上述のように作製した電池の正極リードと負極リードとを、充放電試験装置(アスカ電子社製)の対応する端子に接続し、最大電圧4.2V、電流レート5Cで定電流定電圧充電し、充電完了後、電流レート5Cにて2.5Vまで定電流放電させた。これを1000サイクル繰り返した。初回放電時に測定した容量からエネルギー密度(Wh/kg)を算出し、サイクル後の容量からサイクル容量維持率(1000サイクル時放電容量/初回放電容量×100)を算出した。容量維持率は92%であった。測定結果を表1に示す。
(4) Charging / discharging test The positive electrode lead and the negative electrode lead of the battery produced as described above were connected to corresponding terminals of the charging / discharging test apparatus (manufactured by Asuka Electronics Co., Ltd.), and the maximum voltage was 4.2 V and the current rate was 5 C. The battery was charged with a constant current and a constant voltage, and after charging was completed, the battery was discharged at a constant current rate of 2.5 V at a current rate of 5C. This was repeated 1000 cycles. The energy density (Wh / kg) was calculated from the capacity measured at the first discharge, and the cycle capacity retention ratio (discharge capacity at 1000 cycles / initial discharge capacity × 100) was calculated from the capacity after the cycle. The capacity retention rate was 92%. The measurement results are shown in Table 1.

(5)釘刺し試験
前述のように作製した電池の正極リードと負極リードとを、充放電試験装置(アスカ電子社製)の対応する端子に接続し、最大電圧4.2V、電流レート5Cで定電流定電圧充電した。釘径φ5mmの鉄製の釘を用意し、金属製基盤上にリチウムイオン二次電池を載置した。リチウムイオン二次電池の中央部に、正極及び負極の積層方向に向かって釘刺し速度15mm/秒で釘を刺し、アルミラミネートを貫通させた。釘刺しから10分経過するまで観察したが、セルの異常発熱及び発火は生じなかった。観察結果を表1に示す。ここで、〇は異常が観察されなかったことを、×は異常発熱や発火が生じたことを意味する。
(5) Nail penetration test The positive electrode lead and the negative electrode lead of the battery manufactured as described above were connected to corresponding terminals of a charge / discharge test apparatus (manufactured by Asuka Electronics Co., Ltd.), and the maximum voltage was 4.2 V and the current rate was 5 C. It was charged with constant current and constant voltage. An iron nail having a nail diameter of 5 mm was prepared, and a lithium ion secondary battery was placed on a metal base. A nail was pierced at the central portion of the lithium ion secondary battery in the stacking direction of the positive electrode and the negative electrode at a nail penetration speed of 15 mm / sec to penetrate the aluminum laminate. Observation was made until 10 minutes had passed since the nail penetration, but no abnormal heating or ignition of the cell occurred. The observation results are shown in Table 1. Here, ○ means that no abnormality was observed, and × means that abnormal heat generation or ignition occurred.

(実施例2)
単位面積当たりの負極初度充電容量をx[mAh/cm2]、単位面積当たりの正極初度充電容量をy[mAh/cm2]としたときのxとyの関係が、y/x=0.6となるように負極合材層の塗工量(片面当たり)を10.6mg/cm2に変更した以外は全て実施例1と同一条件にして電池を作製し評価を行った。容量維持率は87%であり、釘刺しによる安全性試験においては、セルの異常発熱及び発火は生じなかった。
(Example 2)
The relationship between x and y when the negative electrode initial charge capacity per unit area is x [mAh / cm 2 ] and the positive electrode initial charge capacity per unit area is y [mAh / cm 2 ] is y / x = 0. A battery was produced and evaluated under the same conditions as in Example 1 except that the coating amount (per one side) of the negative electrode mixture layer was changed to 10.6 mg / cm 2 so as to be 6. The capacity maintenance rate was 87%, and in the safety test by nail penetration, no abnormal heating or ignition of the cell occurred.

(実施例3)
単位面積当たりの負極初度充電容量をx[mAh/cm2]、単位面積当たりの正極初度充電容量をy[mAh/cm2]としたときのxとyの関係が、y/x=0.85となるように負極合材層の塗工量(片面当たり)を7.6mg/cm2に変更した以外は全て実施例1と同一条件にして電池を作製し評価を行った。容量維持率は91%であり、釘刺しによる安全性試験においては、セルの異常発熱及び発火は生じなかった。
(Example 3)
The relationship between x and y when the negative electrode initial charge capacity per unit area is x [mAh / cm 2 ] and the positive electrode initial charge capacity per unit area is y [mAh / cm 2 ] is y / x = 0. A battery was prepared and evaluated under the same conditions as in Example 1 except that the coating amount (per one side) of the negative electrode mixture layer was changed to 7.6 mg / cm 2 so as to be 85. The capacity maintenance rate was 91%, and in the safety test by nail penetration, no abnormal heating or ignition of the cells occurred.

(比較例1)
単位面積当たりの負極初度充電容量をx[mAh/cm2]、単位面積当たりの正極初度充電容量をy[mAh/cm2]としたときのxとyの関係が、y/x=0.95となるように負極合材層の塗工量(片面当たり)を6.8mg/cm2に変更した以外は全て実施例1と同一条件にして電池を作製し評価を行った。容量維持率は92%であり、釘刺しによる安全性試験においては、セルの異常発熱及び発火が生じた。
(Comparative Example 1)
The relationship between x and y when the negative electrode initial charge capacity per unit area is x [mAh / cm 2 ] and the positive electrode initial charge capacity per unit area is y [mAh / cm 2 ] is y / x = 0. A battery was produced and evaluated under the same conditions as in Example 1 except that the coating amount (per one side) of the negative electrode mixture layer was changed to 6.8 mg / cm 2 so as to be 95. The capacity maintenance rate was 92%, and in the safety test by nail penetration, abnormal heating and ignition of the cell occurred.

(比較例2)
単位面積当たりの負極初度充電容量をx[mAh/cm2]、単位面積当たりの正極初度充電容量をy[mAh/cm2]としたときのxとyの関係が、y/x=0.55となるように極合材層の塗工量(片面当たり)を11.7mg/cm2に変更した以外は全て実施例1と同一条件にして電池を作製し評価を行った。容量維持率は78%であり、釘刺しによる安全性試験においては、セルの異常発熱及び発火は生じなかった。実施例1〜3及び比較例1、2の結果を表1に示す。
(Comparative Example 2)
The relationship between x and y when the negative electrode initial charge capacity per unit area is x [mAh / cm 2 ] and the positive electrode initial charge capacity per unit area is y [mAh / cm 2 ] is y / x = 0. A battery was prepared and evaluated under the same conditions as in Example 1 except that the coating amount (per one side) of the electrode mixture layer was changed to 11.7 mg / cm 2 so as to be 55. The capacity maintenance rate was 78%, and in the safety test by nail penetration, abnormal heating and ignition of the cell did not occur. The results of Examples 1 to 3 and Comparative Examples 1 and 2 are shown in Table 1.

Figure 2013084566
Figure 2013084566

(実施例4)
単位面積当たりの負極初度充電容量をx[mAh/cm2]、単位面積当たりの正極初度充電容量をy[mAh/cm2]としたときのxとyとの関係が、y/x=0.92となるように負極合材層の塗工量(片面当たり)を7.0mg/cm2に変更した以外は全て実施例1と同一条件にして電池を作製し評価を行った。容量維持率は90%であり、釘刺しによる安全性試験においては、セルの異常発熱及び発火は生じなかった。
Example 4
The relationship between x and y when the negative electrode initial charge capacity per unit area is x [mAh / cm 2 ] and the positive electrode initial charge capacity per unit area is y [mAh / cm 2 ] is y / x = 0. A battery was fabricated and evaluated under the same conditions as in Example 1 except that the coating amount (per one side) of the negative electrode mixture layer was changed to 7.0 mg / cm 2 so as to be .92. The capacity maintenance rate was 90%, and in the safety test by nail penetration, abnormal heating and ignition of the cell did not occur.

(実施例5)
正極合材層の第二活物質をLiNi0.8Co0.1Al0.12に置き換えると共に、単位面積当たりの負極初度充電容量をx[mAh/cm2]、単位面積当たりの正極初度充電容量をy[mAh/cm2]としたときのxとyとの関係が、y/x=0.92となるように負極合材層の塗工量(片面当たり)を7.3mg/cm2に変更した以外は全て実施例1と同一条件にして電池を作製し評価を行った。容量維持率は90%であり、釘刺しによる安全性試験においては、セルの異常発熱及び発火は生じなかった。
(Example 5)
The second active material of the positive electrode mixture layer is replaced with LiNi 0.8 Co 0.1 Al 0.1 O 2 , the negative electrode initial charge capacity per unit area is x [mAh / cm 2 ], and the positive electrode initial charge capacity per unit area is y [ The coating amount (per one side) of the negative electrode mixture layer was changed to 7.3 mg / cm 2 so that the relationship between x and y when mAh / cm 2 ] was set to y / x = 0.92 A battery was prepared and evaluated under the same conditions as in Example 1 except for the above. The capacity maintenance rate was 90%, and in the safety test by nail penetration, abnormal heating and ignition of the cell did not occur.

(実施例6)
正極合材層の第二活物質をLiNi0.6Co0.2Mn0.22に置き換えると共に、単位面積当たりの負極初度充電容量をx[mAh/cm2]、単位面積当たりの正極初度充電容量をy[mAh/cm2]としたときのxとyとの関係が、y/x=0.92となるように負極合材層の塗工量(片面当たり)を6.1mg/cm2に変更した以外は全て実施例1と同一条件にして電池を作製し評価を行った。容量維持率は89%であり、釘刺しによる安全性試験においては、セルの異常発熱及び発火は生じなかった。
(Example 6)
The second active material of the positive electrode mixture layer is replaced with LiNi 0.6 Co 0.2 Mn 0.2 O 2 , the negative electrode initial charge capacity per unit area is x [mAh / cm 2 ], and the positive electrode initial charge capacity per unit area is y [ The coating amount (per one side) of the negative electrode mixture layer was changed to 6.1 mg / cm 2 so that the relationship between x and y when mAh / cm 2 ] was set to y / x = 0.92 A battery was prepared and evaluated under the same conditions as in Example 1 except for the above. The capacity maintenance rate was 89%, and in the safety test by nail penetration, no abnormal heating or ignition of the cell occurred.

(実施例7)
正極合材層の第二活物質をLiNi0.5Co0.3Mn0.22に置き換えると共に、単位面積当たりの負極初度充電容量をx[mAh/cm2]、単位面積当たりの正極初度充電容量をy[mAh/cm2]としたときのxとyとの関係が、y/x=0.92となるように負極合材層の塗工量(片面当たり)を6.1mg/cm2に変更した以外は全て実施例1と同一条件にして電池を作製し評価を行った。容量維持率は89%であり、釘刺しによる安全性試験においては、セルの異常発熱及び発火は生じなかった。
(Example 7)
The second active material of the positive electrode mixture layer is replaced with LiNi 0.5 Co 0.3 Mn 0.2 O 2 , the negative electrode initial charge capacity per unit area is x [mAh / cm 2 ], and the positive electrode initial charge capacity per unit area is y [ The coating amount (per one side) of the negative electrode mixture layer was changed to 6.1 mg / cm 2 so that the relationship between x and y when mAh / cm 2 ] was set to y / x = 0.92 A battery was prepared and evaluated under the same conditions as in Example 1 except for the above. The capacity maintenance rate was 89%, and in the safety test by nail penetration, no abnormal heating or ignition of the cell occurred.

(比較例3)
正極合材層の第二活物質をLiNi0.6Co0.2Mn0.22に置き換えると共に、単位面積当たりの負極初度充電容量をx[mAh/cm2]、単位面積当たりの正極初度充電容量をy[mAh/cm2]としたときのxとyとの関係が、y/x=0.95となるように負極合材層の塗工量(片面当たり)を5.9mg/cm2に変更した以外は全て実施例1と同一条件にして電池を作製し評価を行った。容量維持率は90%であり、釘刺しによる安全性試験においては、セルの異常発熱及び発火が生じた。
(Comparative Example 3)
The second active material of the positive electrode mixture layer is replaced with LiNi 0.6 Co 0.2 Mn 0.2 O 2 , the negative electrode initial charge capacity per unit area is x [mAh / cm 2 ], and the positive electrode initial charge capacity per unit area is y [ The coating amount of the negative electrode mixture layer (per one side) was changed to 5.9 mg / cm 2 so that the relationship between x and y when mAh / cm 2 ] was set to y / x = 0.95. A battery was prepared and evaluated under the same conditions as in Example 1 except for the above. The capacity maintenance rate was 90%, and in the safety test by nail penetration, abnormal heating and ignition of the cell occurred.

(比較例4)
正極合材層の第二活物質をLiNi0.5Co0.3Mn0.22に置き換えると共に、単位面積当たりの負極初度充電容量をx[mAh/cm2]、単位面積当たりの正極初度充電容量をy[mAh/cm2]としたときのxとyとの関係が、y/x=0.95となるように負極合材層の塗工量(片面当たり)を5.9mg/cm2に変更した以外は全て実施例1と同一条件にして電池を作製し評価を行った。容量維持率は90%であり、釘刺しによる安全性試験においては、セルの異常発熱及び発火は生じた。
(Comparative Example 4)
The second active material of the positive electrode mixture layer is replaced with LiNi 0.5 Co 0.3 Mn 0.2 O 2 , the negative electrode initial charge capacity per unit area is x [mAh / cm 2 ], and the positive electrode initial charge capacity per unit area is y [ The coating amount of the negative electrode mixture layer (per one side) was changed to 5.9 mg / cm 2 so that the relationship between x and y when mAh / cm 2 ] was set to y / x = 0.95. A battery was prepared and evaluated under the same conditions as in Example 1 except for the above. The capacity maintenance rate was 90%, and in the safety test by nail penetration, abnormal heating and ignition of the cell occurred.

(比較例5)
正極合材層の第二活物質をLiNi0.6Co0.2Mn0.22に置き換えると共に、単位面積当たりの負極初度充電容量をx[mAh/cm2]、単位面積当たりの正極初度充電容量をy[mAh/cm2]としたときのxとyとの関係が、y/x=0.55となるように負極合材層の塗工量(片面当たり)を10mg/cm2に変更した以外は全て実施例1と同一条件にして電池を作製し評価を行った。容量維持率は76%であり、釘刺しによる安全性試験においては、セルの異常発熱及び発火は生じなかった。
(Comparative Example 5)
The second active material of the positive electrode mixture layer is replaced with LiNi 0.6 Co 0.2 Mn 0.2 O 2 , the negative electrode initial charge capacity per unit area is x [mAh / cm 2 ], and the positive electrode initial charge capacity per unit area is y [ Except for changing the coating amount of the negative electrode mixture layer (per one side) to 10 mg / cm 2 so that the relationship between x and y with respect to mAh / cm 2 ] is y / x = 0.55. All the batteries were fabricated and evaluated under the same conditions as in Example 1. The capacity maintenance rate was 76%, and in the safety test by nail penetration, abnormal heating and ignition of the cell did not occur.

(比較例6)
正極合材層の第二活物質をLiNi0.5Co0.3Mn0.22に置き換えると共に、単位面積当たりの負極初度充電容量をx[mAh/cm2]、単位面積当たりの正極初度充電容量をy[mAh/cm2]としたときのxとyとの関係が、y/x=0.55となるように負極合材層の塗工量(片面当たり)を10mg/cm2に変更した以外は全て実施例1と同一条件にして電池を作製し評価を行った。容量維持率は75%であり、釘刺しによる安全性試験においては、セルの異常発熱及び発火は生じなかった。実施例4〜7及び比較例3〜6の結果を表2及び表3に示す。
(Comparative Example 6)
The second active material of the positive electrode mixture layer is replaced with LiNi 0.5 Co 0.3 Mn 0.2 O 2 , the negative electrode initial charge capacity per unit area is x [mAh / cm 2 ], and the positive electrode initial charge capacity per unit area is y [ Except for changing the coating amount of the negative electrode mixture layer (per one side) to 10 mg / cm 2 so that the relationship between x and y with respect to mAh / cm 2 ] is y / x = 0.55. All the batteries were fabricated and evaluated under the same conditions as in Example 1. The capacity maintenance rate was 75%, and in the safety test by nail penetration, no abnormal heating or ignition of the cell occurred. The results of Examples 4 to 7 and Comparative Examples 3 to 6 are shown in Table 2 and Table 3.

Figure 2013084566
Figure 2013084566

Figure 2013084566
Figure 2013084566

上述の実施例1から実施例7の実験結果からわかるように、単位面積当たりの負極初度充電容量をx[mAh/cm2]、単位面積当たりの正極初度充電容量をy[mAh/cm2]としたときのy/xの値を0.6から0.92の範囲にすることで、負極のリチウム脱マージンが大きくなり、釘刺しによる安全試験で良好な結果が得られた。y/xの値が0.6の下限より小さくなると、釘刺しによる安全試験では良好な結果が得られるものの、電流負荷試験において良好な結果が得られなかった。これは、リチウムイオンの負極での脱マージンを必要以上に多くとり過ぎ、正極と負極の充電容量にアンバランスが生じたためと考えられる。また、y/xの値を0.92より大きくすると、釘刺しによる安全試験では、従来と同様に負極のリチウムイオン脱マージンが低く、セルの異常発熱に至ったと考えられる。 As can be seen from the experimental results of Examples 1 to 7, the negative electrode initial charge capacity per unit area is x [mAh / cm 2 ], and the positive electrode initial charge capacity per unit area is y [mAh / cm 2 ]. When the value of y / x was in the range of 0.6 to 0.92, the lithium demarcation margin of the negative electrode was increased, and good results were obtained in a safety test by nail penetration. When the value of y / x was smaller than the lower limit of 0.6, a good result was obtained in the safety test by nail penetration, but a good result was not obtained in the current load test. This is thought to be due to an unbalanced charge capacity between the positive electrode and the negative electrode due to excessive demarcation at the negative electrode of lithium ions. Further, when the value of y / x is larger than 0.92, it is considered that in the safety test by nail penetration, the lithium ion demargin of the negative electrode is low as in the conventional case, leading to abnormal heat generation of the cell.

なお、本発明は上記の実施の形態の構成及び実施例に限定されるものではなく、発明の要旨の範囲内で種々変形が可能である。   In addition, this invention is not limited to the structure and Example of said embodiment, A various deformation | transformation is possible within the range of the summary of invention.

20、30 リチウムイオン二次電池
21、31 正極
21a、31a 正極合材層
21b、31b 正極集電体
22、32 負極
22a、32a 負極合材層
22b、32b 負極集電体
23、33 セパレータ
34 電極ユニット
36、37 リード
20, 30 Lithium ion secondary battery 21, 31 Positive electrode 21a, 31a Positive electrode mixture layer 21b, 31b Positive electrode collector 22, 32 Negative electrode 22a, 32a Negative electrode mixture layer 22b, 32b Negative electrode collector 23, 33 Separator 34 Electrode Unit 36, 37 lead

Claims (7)

カーボンを被覆したリン酸バナジウムリチウム及びリチウムニッケル複合酸化物を正極の活物質に含み、且つリチウムイオン脱挿入可能なカーボン系活物質を負極の活物質に含み、単位面積当たりの負極初度充電容量をx[mAh/cm]、単位面積当たりの正極初度充電容量をy[mAh/cm]としたときのxとyとの関係が、0.6≦y/x≦0.92となることを特徴とする非水電解質二次電池。 Carbon-coated lithium vanadium phosphate and lithium nickel composite oxide are included in the active material of the positive electrode, and a carbon-based active material capable of lithium ion desorption / insertion is included in the active material of the negative electrode, and the initial charge capacity of the negative electrode per unit area is increased. When x [mAh / cm 2 ] and the positive electrode initial charge capacity per unit area are y [mAh / cm 2 ], the relationship between x and y is 0.6 ≦ y / x ≦ 0.92. A non-aqueous electrolyte secondary battery. 前記負極初度充電容量及び前記正極初度充電容量は、前記負極及び前記正極のそれぞれの塗工量により決定されることを特徴とする請求項1に記載の非水電解質二次電池。
解質二次電池。
The nonaqueous electrolyte secondary battery according to claim 1, wherein the negative electrode initial charge capacity and the positive electrode initial charge capacity are determined by respective coating amounts of the negative electrode and the positive electrode.
Denatured secondary battery.
前記正極の活物質に含まれる前記リチウムニッケル複合酸化物の割合は、5〜95質量%であることを特徴とする請求項1又は2の何れか1項に記載の非水電解質二次電池。   3. The non-aqueous electrolyte secondary battery according to claim 1, wherein a ratio of the lithium nickel composite oxide contained in the active material of the positive electrode is 5 to 95 mass%. 前記リチウムニッケル複合酸化物中のニッケル元素が、リチウム原子1モルに対して、0.5モル以上、0.8モル以下含まれていることを特徴とする請求項1から3の何れか1項に記載の非水電解質二次電池。   The nickel element in the lithium nickel composite oxide is contained in an amount of 0.5 mol or more and 0.8 mol or less with respect to 1 mol of a lithium atom. The non-aqueous electrolyte secondary battery described in 1. 前記リチウムニッケル複合酸化物が、原子番号11以上のNiとは異なる金属元素を含むことを特徴とする請求項1から4の何れか1項に記載の非水電解質二次電池。   5. The non-aqueous electrolyte secondary battery according to claim 1, wherein the lithium nickel composite oxide contains a metal element different from Ni having an atomic number of 11 or more. 前記金属元素が、Co、Mn、Al及びMgから選択される元素であることを特徴とする請求項5に記載の非水電解質二次電池。   6. The nonaqueous electrolyte secondary battery according to claim 5, wherein the metal element is an element selected from Co, Mn, Al, and Mg. 前記リン酸バナジウムリチウムが、
Li2−y(POで表され、
MがFe、Co、Mn、Cu、Zn、Al、Sn、B、Ga、Cr、V、Ti、Mg、Ca、Sr、Zrからなる群より選ばれる一種以上であり、且つ、
1≦x≦3、
0≦y<2、
2≦z≦3
を満足する材料であることを特徴とする請求項1から6の何れか1項に記載の非水電解質二次電池。
The lithium vanadium phosphate is
Represented by Li x V 2-y M y (PO 4) z,
M is one or more selected from the group consisting of Fe, Co, Mn, Cu, Zn, Al, Sn, B, Ga, Cr, V, Ti, Mg, Ca, Sr, and Zr, and
1 ≦ x ≦ 3,
0 ≦ y <2,
2 ≦ z ≦ 3
The nonaqueous electrolyte secondary battery according to claim 1, wherein the nonaqueous electrolyte secondary battery is a material satisfying the requirements.
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